Evaporator



May 19, 1931. c. E. 1.. LIPMAN EVAPORATOR Filed my 3, 1930 jig 1.

2 She'etsShee't 1 Patented May 19, 1931 UNITED-STATES PATENT OFFICE CARL E. I. LIPMAN, OF- CHICAGO; ILLINOIS, ASSIGNOR TO LIIMAN PATENTS GOR- PORATION, OF CHICAGO, ILLINOIS, A. CORPORATION OF DELAWARE EVAI'ORATOR Application flied Kay 3, 1930. Serial No. 449,377.

This invention relates to refrigerating systems and more particularly to that unit thereof known as the evaporator.

It is the purpose of this invention t pro- 5 vide such an evaporator which is particu arly well adapted for use in a high pressure float feed system and which will provide a compartment of relatively low temperature such as a freezing compartment for ice cubes and which will also constitute the cooling medium foranother compartment wherein the temperature is not as low as the previously mentioned compartment, such as the food compartment of a refrigerator.

It is also the purpose of this invention to provide such an evaporator which will not cause dehydration of the articles contained in the latter mentioned chamber.

It is a still further object of this invention to provide an evaporator having means for withdrawing therefrom any oil which may have been carried over bythe refrigerant.

In accordance with this invention the evaporator is constructed with two refrigerant chambers, one a relatively small chamber which is separate from but in communication with a second refrigerant chamber the latter chamber receiving its refrigerant from the first chamber. The refrigerant chambers may be insulated as well as be spaced from and condenser and maybe formed to enclose the freezing compartment. 'The second chamber is arranged to receive its refrigerant from the first chamber but is also so arranged that the refrigerant need not necessarily circulate completely through the first chamber prior to its entry into the second chamber. By this arrangement the 'seco'nd chamber can be designed to cool the food compartment to the desired degree without extracting any appreciable moisture from the food compartment or contents thereof.

It is advantageous in some instances to maintain greater independence between the two refrigerant chambers and in such instances the space between the two chambers may be filled with some insulating medium.

The evaporator if used in connection with each other if desired. The first chamber re-' ceives the refrigerant from the compressor a system in which oil is likely to occur in the evaporator may be provided with means associated with the suctionline from the evaporator to the compressor for inspirating or 'aspiratinlg the oil from the evaporator along with t e gaseous refrigerant being removed from the evaporator.

A better understanding of this invention will be had from a consideration of the following'description given in connection with the drawings in which:

Fig. 1 is a longitudinal vertical section I through approximately the centerof an evaporator constructed in accordance with this invention. v I

Fig. 2 is a section on line 2-2 of Fig. 1.

-Fig. 3 is a longitudinal vertical section I through a slighty modified form of this invention. Referring particularly to the form of this invention illustrated in Figs. 1 and 2,- it is seen that the evaporator is formed of three cup-like shells or casings, 1, 2 and 3 fitted con:

centrically within each other and spaced.

from each other, the edges of the shells being welded or otherwise secured together at the .open ends thereof as at 4. Shells 1 and 2 are relatively close together thus providing a relatively thin refrigerant chamber 6 therebetween,- the chamber extending around the entire side and one end; The intermediate shell 2 is provided with an opening 7 bounded by an upturned lip or flange 8 which opens upwardly with the evaporator in its normal position. This opening 7 provides communication between the inner chamber 6 and the outer refrigerant chamber 9 constituting the 'space between the intermediate shell 2 and the outer shell 3. The outer shell 3 may be I compressor of the refrigerating system (not shown) used in connection with the evaporator. I

From the above description is seen that there is provided an evaporator having an inner refrigerant chamber which encloses and cools a compartment 14: which may be utilized as a freezing compartment and an outer refrigerant chamber 9 which receives refrigerant from the inner chamber and serves as the cooling medium for the compartment within which the evaporator is placed. The evaporator if provided with a suificient amount of fin surface will reduce the temperature of the compartment within which it is placed without dehydrating articles placed therein.

In operation liquid refrigerant will be supplied to chamber 6 through tube 12 and will substantially fill the chamber 6. During running periods of the compressor the refrigerant in chamber 6 will boil and the level thereof rise,'part of the refrigerant boiling and splashing over into the outer chamber 9 moistening the outer surfaces of shell 2 and the inner surface ofshell 3. The vaporized refrigerant caused by the vaporization of the refrigerant in the two chambers is drawn off through tube 13. When the compressor stops, the liquid refrigerant in chamber 9 will pass over into the cooler chamber 6 and recondense.

From the above it can be seen that therefrigerant directly from the condenser is deposited in the inner chamber 6 from where sufficient amounts are boiled over into the outer chamber thus providing two refrigerant chambers with the refrigerant distributed therein in the most eflicient manner for the purpose desired, that is, for providing a freezing compartment and a refrigeratmg compartment.

In order to provide for a positive return to the compressor of any oil which may come over into the evaporator with the refrigerant there is provided means for injecting, e ecting or aspirating the oil in the evaporator back to the compressor. For this purpose there is provided a U-shaped tube 16 of slightly less diameter than the outlet tube 13 and having one end disposed within the inner end of the outlet tube 13 to create a suction in tube 16. The U-tube 16 extends downwardly between the end portions of shells 2 and 3, the u per end being disposed above the level 0 the liquid and oil in the evaporator. The tube is provided with a small aperture 17 adjacent its upper end and a small aperture 18 at the bot-.

tom of the U-portion.

It is obvious that the tube may be placed on the outside of the shell if desired with the open end of'the tube and apertures 17 and 18 communicating with the chamber between shells 2 and 3. In some instances it may be desirable to have the tube 16 close tube 13 entirely in order to produce greater suction and a correspondingly greater inspirating action in tube 16.

The operation of the inspirating or aspirating tube 16 is as follows; When the compressor is running a suction is created in tube 13 and consequently in the tube 16. The tube 16 will suck mostly gas with some liquid such as oil through the apertures 17 and 18 as is common in aspirators and ejectors. The oil will thus be removed with the refrigerant and return through the refrigerant suction line to the compressor in small quantities. In this manner oil of liquor slugs are prevented from getting into the compressor since there is always more gas drawn in than oil or liquor. If the oil conditions do not warrant the inclusion of the inspirating tube this tube may be omitted. On the other hand if the oil is excessive the outer chamber. may be entirely filled with oil to the level of tube 13. Any additional oil would flow over into tube 13 and back .to the compressor. The oil in the outer chamber would become chilled and act as a cooling medium.

Referring to the modification shown in Fig. 3 it will be seen that the evaporator is formed of four cuplike shells 21, 22, 23 and 24 arranged concentrically one within the other and secured together at their open edges 25. The shells are arranged to provide spaced refrigerant chambers 26 and 29 the two chambers being separated by an insulating chamber 30 between walls 22 and 23. If desired this chamber may be evacuated or may be filled/with any suitable insulation material through suitable openings. As in the prior modification the shell 22 is provided with an opening 27 bounded by rims 28, and 28a struck upwardly and downwardly respective ly from shells 22 and 23 respectively estabhshing communication between refrigerant chambers 26 and 29. The inner chamber is provided with an inlet 32 and the outer cham her is similarly provided with an outlet 33.

In this form of the invention the oil removing tube is omitted although it is obvious that it could be applied as is shown in Figs. 1 and 2.

From the above it is seen that a very efiicient evaporator has been provided which includes a chamber for rapid freezin due to the localizing of the main body of re rigerant in the inner chamber, which provides for the refrigeration of a larger compartment without dehydratin the contents thereof and which is self-de rosting. This latter feature is due to the fact that the outer refrigerant chamber does not permanently contain an appreciable amount of liquid refrigerant, the inner surfaces thereof being only wetted by the refrigerant. Should any liquid refrigerant get over into the bottom of the outer chamber it will vaporize between running periods of the compressor and pass back into the inner chamber.

It is obvious that minor changes may be made in the details of construction without departing from the spirit and scope of this invention as defined in the claims appended hereto.

I claim:

1. An evaporator comprising a lurality of spaced shells forming an inner re rigerantchamber between one air thereof and an outer refrigerant cham er between another pair thereof, said inner chamber being in communication with said outer chamber, a liquid refrigerant supply connection to said inner chamber and a suction connectlon to said .outer chamber.

,refrigerant chamber between two of said shells and an outer refrigerant chamber between another pair of said shells one of the shells forming said inner chamber having an opening therethrough to establish communiaction between said chambers, a liquid refrigerant supply connection to said inner chamber and a suction connection to said outer chamber.

4. An evaporator comprising a plurality of spaced shells formed to provide a plurality of spaced concentric refrigerating chambers therebetween, said chambers being in communication with each other, a liquid refrigerant supply to one of said chambers and I: suction connection to another of said chamers.

5. An evaporator comprising a plurality of spacedshells formed to provide a plurality of spaced concentric refrigerating chambers therebetween, means for insulating said chambers from each other, said chambers being in communication with each other, a liquid refrigerant supply to one of said cham bers and a suction connection to another of said chambers.

6. An evaporator comprising .a plurality of spaced shells forming an inner refrigerant chamber between two of said shells and an outer refrigerant chamber between two of said shells, said chambers being in communi cation-with each other, a liquid refrigerant supply connection to said inner chamber and asuction connection tosaid outer chamber,

and means for extracting a liquid from said chambers.

7. An evaporator comprising a lurality of spaced shells forming an inner re rigerant chamber between two of said shells and an outer refrigerant chamber between two of said shells, said chambers being in communitween two of said shells, said ing spaced from each other but in communi-- cation with each other, a liquid supply connection to said inner chamber and a suction connection to said outer chamber and means I for inspirating liquid from said chambers,

8. An evaporator comprisinga lurality of spaced shells forming an inner re rigerant chamber between two of said shells and an outer refrigerant chamber between two of said shells, said chambers being in communication with each other, a liquid refrigerant supply connection to said inner chamber and and means associated with said suction line for inspirating liquid lubricant from said chambers into said suction connection.

9. An evaporator comprising a plurality of spaced shells forming an inner refrigerant chamber between two of said shells and an outer -refrigerant chamber between two of said shells, said chambers being in communication with each other, a liquid refrigerant supply connection to said inner chamber, a suction connection to said outer chamber and means for inspirating liquid oil from said chambers comprising'an inspirating tube asa suction connection to said outer chamber,

sociated with said suction line and extending 1 into'said outer refrigerant chamber.

10. An evaporator comprising a plurality 'of spaced shells forming an inner refrigerant chamber between two of said shells and an outer refrigerant chamber between two of said shells, said chambers being in communication with each other, a liquid supply connection to said inner chamber, a suction connection to said outer chamber and means for inspirating oil from said chambers comprising a tube associated with said suction line and extending into said outer refrigerant chamber, said tube having an aperture below the normal liquid level and a relatively larger aperture above the liquid level.

. 11. An evaporator comprising a plurality of spaced shel s forming an inner refrigerant chamber between two of said shells and an outer refrigerant chamber between two of said shells, said chambers being in communication with eachother, a liquid refrigerant supply connection to the inner chamber, a suction connection to the outer chamber, and means for inspirating oil from said chambers into said suction connection comprising an open ended tube having one end terminatingin'said suction connectlon, said tube extending into one of said chambers below the nori-\ mal level of liquid in said chamber and terminating in an 0 en end above the normal liquid level of said chamber.

llO

12. An evaporator comprising a plurality of spaced cup-shaped shells disposed one within the other and having their open peripheral edges sealed together to form an inner refrigerant chamber between two of said shells and an outer refrigerant chamber bechambers becation with each other a liquid supply connection to said inner chamber and a suction connection to said outer chamber.

13. An evaporator com risin a plurality of spaced cup-shaped sl ells isposed one within the other and having their open peripheral edges sealed together to form an inner refrigerant chamber between two of said shells and an outer refrigerant chamber between two of said shells, said chambers being in communication with each other, a liquid supply connection to said inner chamber, a suctlon connection to said outer chamber, and means for inspirating oil from said chambers into said suction connection.

14. An evaporator comprising a plurality of spaced cup-shaped shells disposed one within the other and havin their open peripheral edges sealed toget er to form an inner refrigerant chamber between two of said shells and an outer refrigerant chamber between two of said shells, said chambers being in communication with each other, a liquid supply connection to said inner chamber, a suction connection to said outer chamber and means for inspirating oil from said chambers into said suction connection coinprising a tube in communication with said suction connection and with the outer refrigeramt chamber and having a restricted opening below the normal hquid level in said chamber and an unrestricted opening above the normal liquid level in said chamber.

In witness of the foregoing I afiix my signature.

CARL. L. LIPMAN. 

